<?php 
/**
 * HTML helper class.
 *
 * $Id: html.php 4376 2009-06-01 11:40:39Z samsoir $
 *
 * @package    Core
 * @author     Kohana Team
 * @copyright  (c) 2007-2008 Kohana Team
 * @license    http://kohanaphp.com/license.html
 */
class html {

    // Enable or disable automatic setting of target="_blank"
    public static $windowed_urls = FALSE;

    /**
     * Convert special characters to HTML entities
     *
     * @param   string   string to convert
     * @param   boolean  encode existing entities
     * @return  string
     */
    public static function specialchars($str, $double_encode = TRUE) {
        // Force the string to be a string
        $str = (string) $str;

        // Do encode existing HTML entities (default)
        if ($double_encode === TRUE) {
            $str = htmlspecialchars($str, ENT_QUOTES, 'UTF-8');
        }
        else {
            // Do not encode existing HTML entities
            // From PHP 5.2.3 this functionality is built-in, otherwise use a regex
            if (version_compare(PHP_VERSION, '5.2.3', '>=')) {
                $str = htmlspecialchars($str, ENT_QUOTES, 'UTF-8', FALSE);
            }
            else {
                $str = preg_replace('/&(?!(?:#\d++|[a-z]++);)/ui', '&amp;', $str);
                $str = str_replace(array('<', '>', '\'', '"'), array('&lt;', '&gt;', '&#39;', '&quot;'), $str);
            }
        }

        return $str;
    }

    /**
     * Perform a html::specialchars() with additional URL specific encoding.
     *
     * @param   string   string to convert
     * @param   boolean  encode existing entities
     * @return  string
     */
    public static function specialurlencode($str, $double_encode = TRUE) {
        return str_replace(' ', '%20', html::specialchars($str, $double_encode));
    }

    /**
     * Create HTML link anchors.
     *
     * @param   string  URL or URI string
     * @param   string  link text
     * @param   array   HTML anchor attributes
     * @param   string  non-default protocol, eg: https
     * @param   boolean option to escape the title that is output
     * @return  string
     */
    public static function anchor($uri, $title = NULL, $attributes = NULL, $protocol = NULL, $escape_title = FALSE) {
        if ($uri === '') {
            $site_url = url::base(FALSE);
        }
        elseif (strpos($uri, '#') === 0) {
            // This is an id target link, not a URL
            $site_url = $uri;
        }
        elseif (strpos($uri, '://') === FALSE) {
            $site_url = url::site($uri, $protocol);
        }
        else {
            if (html::$windowed_urls === TRUE AND empty($attributes['target'])) {
                $attributes['target'] = '_blank';
            }

            $site_url = $uri;
        }

        return
                // Parsed URL
                '<a href="'.html::specialurlencode($site_url, FALSE).'"'
                // Attributes empty? Use an empty string
                .(is_array($attributes) ? html::attributes($attributes) : '').'>'
                // Title empty? Use the parsed URL
                .($escape_title ? html::specialchars((($title === NULL) ? $site_url : $title), FALSE) : (($title === NULL) ? $site_url : $title)).'</a>';
    }

    /**
     * Creates an HTML anchor to a file.
     *
     * @param   string  name of file to link to
     * @param   string  link text
     * @param   array   HTML anchor attributes
     * @param   string  non-default protocol, eg: ftp
     * @return  string
     */
    public static function file_anchor($file, $title = NULL, $attributes = NULL, $protocol = NULL) {
        return
                // Base URL + URI = full URL
                '<a href="'.html::specialurlencode(url::base(FALSE, $protocol).$file, FALSE).'"'
                // Attributes empty? Use an empty string
                .(is_array($attributes) ? html::attributes($attributes) : '').'>'
                // Title empty? Use the filename part of the URI
                .(($title === NULL) ? end(explode('/', $file)) : $title) .'</a>';
    }

    /**
     * Similar to anchor, but with the protocol parameter first.
     *
     * @param   string  link protocol
     * @param   string  URI or URL to link to
     * @param   string  link text
     * @param   array   HTML anchor attributes
     * @return  string
     */
    public static function panchor($protocol, $uri, $title = NULL, $attributes = FALSE) {
        return html::anchor($uri, $title, $attributes, $protocol);
    }

    /**
     * Create an array of anchors from an array of link/title pairs.
     *
     * @param   array  link/title pairs
     * @return  array
     */
    public static function anchor_array(array $array) {
        $anchors = array();
        foreach ($array as $link => $title) {
            // Create list of anchors
            $anchors[] = html::anchor($link, $title);
        }
        return $anchors;
    }

    /**
     * Generates an obfuscated version of an email address.
     *
     * @param   string  email address
     * @return  string
     */
    public static function email($email) {
        $safe = '';
        foreach (str_split($email) as $letter) {
            switch (($letter === '@') ? rand(1, 2) : rand(1, 3)) {
                // HTML entity code
                case 1: $safe .= '&#'.ord($letter).';';
                    break;
                // Hex character code
                case 2: $safe .= '&#x'.dechex(ord($letter)).';';
                    break;
                // Raw (no) encoding
                case 3: $safe .= $letter;
            }
        }

        return $safe;
    }

    /**
     * Creates an email anchor.
     *
     * @param   string  email address to send to
     * @param   string  link text
     * @param   array   HTML anchor attributes
     * @return  string
     */
    public static function mailto($email, $title = NULL, $attributes = NULL) {
        if (empty($email))
            return $title;

        // Remove the subject or other parameters that do not need to be encoded
        if (strpos($email, '?') !== FALSE) {
            // Extract the parameters from the email address
            list ($email, $params) = explode('?', $email, 2);

            // Make the params into a query string, replacing spaces
            $params = '?'.str_replace(' ', '%20', $params);
        }
        else {
            // No parameters
            $params = '';
        }

        // Obfuscate email address
        $safe = html::email($email);

        // Title defaults to the encoded email address
        empty($title) and $title = $safe;

        // Parse attributes
        empty($attributes) or $attributes = html::attributes($attributes);

        // Encoded start of the href="" is a static encoded version of 'mailto:'
        return '<a href="&#109;&#097;&#105;&#108;&#116;&#111;&#058;'.$safe.$params.'"'.$attributes.'>'.$title.'</a>';
    }

    /**
     * Generate a "breadcrumb" list of anchors representing the URI.
     *
     * @param   array   segments to use as breadcrumbs, defaults to using Router::$segments
     * @return  string
     */
    public static function breadcrumb($segments = NULL) {
        empty($segments) and $segments = Router::$segments;

        $array = array();
        while ($segment = array_pop($segments)) {
            $array[] = html::anchor
                    (
                    // Complete URI for the URL
                    implode('/', $segments).'/'.$segment,
                    // Title for the current segment
                    ucwords(inflector::humanize($segment))
            );
        }

        // Retrun the array of all the segments
        return array_reverse($array);
    }

    /**
     * Creates a meta tag.
     *
     * @param   string|array   tag name, or an array of tags
     * @param   string         tag "content" value
     * @return  string
     */
    public static function meta($tag, $value = NULL) {
        if (is_array($tag)) {
            $tags = array();
            foreach ($tag as $t => $v) {
                // Build each tag and add it to the array
                $tags[] = html::meta($t, $v);
            }

            // Return all of the tags as a string
            return implode("\n", $tags);
        }

        // Set the meta attribute value
        $attr = in_array(strtolower($tag), Kohana::config('http.meta_equiv')) ? 'http-equiv' : 'name';

        return '<meta '.$attr.'="'.$tag.'" content="'.$value.'" />';
    }

    /**
     * Creates a stylesheet link.
     *
     * @param   string|array  filename, or array of filenames to match to array of medias
     * @param   string|array  media type of stylesheet, or array to match filenames
     * @param   boolean       include the index_page in the link
     * @return  string
     */
    public static function stylesheet($style, $media = FALSE, $index = FALSE) {
        return html::link($style, 'stylesheet', 'text/css', '.css', $media, $index);
    }

    /**
     * Creates a link tag.
     *
     * @param   string|array  filename
     * @param   string|array  relationship
     * @param   string|array  mimetype
     * @param   string        specifies suffix of the file
     * @param   string|array  specifies on what device the document will be displayed
     * @param   boolean       include the index_page in the link
     * @return  string
     */
    public static function link($href, $rel, $type, $suffix = FALSE, $media = FALSE, $index = FALSE) {
        $compiled = '';

        if (is_array($href)) {
            foreach ($href as $_href) {
                $_rel   = is_array($rel) ? array_shift($rel) : $rel;
                $_type  = is_array($type) ? array_shift($type) : $type;
                $_media = is_array($media) ? array_shift($media) : $media;

                $compiled .= html::link($_href, $_rel, $_type, $suffix, $_media, $index);
            }
        }
        else {
            if (strpos($href, '://') === FALSE) {
                // Make the URL absolute
                $href = url::base($index).$href;
            }

            $length = strlen($suffix);

            if ( $length > 0 AND substr_compare($href, $suffix, -$length, $length, FALSE) !== 0) {
                // Add the defined suffix
                $href .= $suffix;
            }

            $attr = array
                    (
                    'rel' => $rel,
                    'type' => $type,
                    'href' => $href,
            );

            if ( ! empty($media)) {
                // Add the media type to the attributes
                $attr['media'] = $media;
            }

            $compiled = '<link'.html::attributes($attr).' />';
        }

        return $compiled."\n";
    }

    /**
     * Creates a script link.
     *
     * @param   string|array  filename
     * @param   boolean       include the index_page in the link
     * @return  string
     */
    public static function script($script, $index = FALSE) {
        $compiled = '';

        if (is_array($script)) {
            foreach ($script as $name) {
                $compiled .= html::script($name, $index);
            }
        }
        else {
            if (strpos($script, '://') === FALSE) {
                // Add the suffix only when it's not already present
                $script = url::base((bool) $index).$script;
            }

            if (substr_compare($script, '.js', -3, 3, FALSE) !== 0) {
                // Add the javascript suffix
                $script .= '.js';
            }

            $compiled = '<script type="text/javascript" src="'.$script.'"></script>';
        }

        return $compiled."\n";
    }

    /**
     * Creates a image link.
     *
     * @param   string        image source, or an array of attributes
     * @param   string|array  image alt attribute, or an array of attributes
     * @param   boolean       include the index_page in the link
     * @return  string
     */
    public static function image($src = NULL, $alt = NULL, $index = FALSE) {
        // Create attribute list
        $attributes = is_array($src) ? $src : array('src' => $src);

        if (is_array($alt)) {
            $attributes += $alt;
        }
        elseif ( ! empty($alt)) {
            // Add alt to attributes
            $attributes['alt'] = $alt;
        }

        if (strpos($attributes['src'], '://') === FALSE) {
            // Make the src attribute into an absolute URL
            $attributes['src'] = url::base($index).$attributes['src'];
        }

        return '<img'.html::attributes($attributes).' />';
    }

    /**
     * Compiles an array of HTML attributes into an attribute string.
     *
     * @param   string|array  array of attributes
     * @return  string
     */
    public static function attributes($attrs) {
        if (empty($attrs))
            return '';

        if (is_string($attrs))
            return ' '.$attrs;

        $compiled = '';
        foreach ($attrs as $key => $val) {
            $compiled .= ' '.$key.'="'.html::specialchars($val).'"';
        }

        return $compiled;
    }

} // End html
